scholarly journals The Yields and Composition of Five Grasses Growing in the Humid Mountains of Puerto Rico, as Affected by Nitrogen Fertilization, Season, and Harvest Procedures

1969 ◽  
Vol 44 (3) ◽  
pp. 107-120
Author(s):  
Ruben Caro-Costas ◽  
José Vicente-Chandler ◽  
Jacinto Figarella
Keyword(s):  
Puerto Rico ◽  
Nitrogen Fertilization ◽  
Slow Growth ◽  
Lignin Content ◽  
Grazing Management ◽  
Yield Response ◽  
Guinea Grass ◽  
Simulated Grazing ◽  
Cutting Management ◽  
Nitrogen Rates

The productivity of Napier, Guinea, Para, Pangola, and molasses grasses, as affected by nitrogen fertilization and season of the year under both cutting and simulated grazing management, were determined under conditions typical of the humid mountain region of Puerto Rico. Molasses grass yielded much less than the others, all of which were very similar in yield, response to nitrogen fertilization, and seasonal growth rates with both harvest procedures, except that Guinea grass outyielded the others with grazing management. With cutting management and 400 pounds of nitrogen per acre yearly, Napier, Guinea, Para, and Pangola grasses yielded about 24,000 pounds of dry matter per acre yearly having about 8 percent of protein. Yields were lower with grazing than with cutting management. Season of the year markedly affected growth of all grasses with lowest yields occurring from December through March. Seasonal variations were accentuated by nitrogen fertilization. Annual yields of the Para, Guinea, Napier, and Pangola grasses increased rapidly with nitrogen rates up to 400 pounds. However, response was generally limited to the 200-pound rate during seasons of slow growth, but was strong up to at least the 400-pound rate at other times. Molasses grass responded only to the application of 200 pounds of nitrogen per acre yearly at all seasons. Protein content of all the grasses was similar, increased with nitrogen rates, was higher during seasons of slow growth, and lower with cutting than with simulated grazing management. Napier grass had the lowest drymatter content, while Guinea grass had a markedly higher calcium and magnesium content than the others. Otherwise, the forages were very similar in mineral and lignin content. There was little difference in efficiency of nitrogen utilization by the highest yielding grasses. Efficiency was lower with grazing management, higher during seasons of fast growth, and decreased with increasing nitrogen rates

scholarly journals Effects of Nitrogen Fertilization and Frequency of Cutting on the Yield and Composition of Pangola Grass in Puerto Rico

1969 ◽  
Vol 45 (1) ◽  
pp. 37-45
Author(s):  
José Vicente-Chandler ◽  
Jacinto Figarella ◽  
Servando Silva
Keyword(s):  
Puerto Rico ◽  
Protein Content ◽  
Nitrogen Fertilization ◽  
Dry Matter ◽  
Slow Growth ◽  
Lignin Content ◽  
Optimum Combination ◽  
Fertilizer Nitrogen ◽  
Harvest Intervals ◽  
Nitrogen Rates

The effects of nitrogen rates ranging from 0 to 1,600 pounds of N per acre yearly and of 30-, 45-, and 60-day harvest intervals on the yield and composition of Pangola grass were determined for 2 consecutive years. Yields increased sharply with nitrogen fertilization up to the 400-pound level, while protein content increased up to the 1,600-pound level. About two-thirds of the fertilizer nitrogen was recovered in the forage when 400 pounds or less were applied per acre yearly. Efficiency of utilization, in terms of dry matter produced per pound of nitrogen, decreased with increasing rates. Yields and lignin content of the forage increased while the protein content decreased with length of harvest interval. A 45-day harvest interval during seasons of flush growth, and a 60-day interval during the season of slow growth, combined with 400 pounds of nitrogen per acre yearly seems to be the optimum combination. Yields varied widely with season of the year.

scholarly journals Effect of Frequency of Application on Response of Guinea Grass to Nitrogen Fertilization

1969 ◽  
Vol 46 (4) ◽  
pp. 342-349
Author(s):  
José Vicente-Chandler ◽  
Servando Silva ◽  
Jacinto Figarella
Keyword(s):  
Puerto Rico ◽  
Protein Content ◽  
Nitrogen Fertilization ◽  
Coastal Region ◽  
Grazing Management ◽  
Potassium Content ◽  
Fertilizer Nitrogen ◽  
Guinea Grass ◽  
Simulated Grazing

The effect of frequency of application on the response of Guinea grass to nitrogen fertilization with cutting and simulated grazing management was studied in the humid coastal region of Puerto Rico. Guinea grass responded strongly in yield and protein content to nitrogen applications up to 800 pounds per acre yearly, regardless of frequency of application or harvest procedure. When cut every 60 days, Guinea grass produced its highest yields and recovered more of the fertilizer nitrogen when it was applied immediately after cutting. Its lowest yields occurred when nitrogen was applied 25 days after cutting. Splitting the applications resulted in yields intermediate between these two. Under grazing management annual yields and protein content of the forage were similar whether the nitrogen was used in eight, four, or two applications yearly. However, seasonal yields and protein and potassium content of the forage varied more widely when there were two applications only of fertilizer yearly. It appears best to apply nitrogen to Guinea grass immediately after each cutting and to make about four applications a year to Guinea grass pastures.

scholarly journals Effects of Nitrogen Fertilization and Frequency of Cutting on the Yield and Composition of Guinea Grass in Puerto Rico

1969 ◽  
Vol 43 (4) ◽  
pp. 228-239
Author(s):  
José Vicente-Chandler ◽  
Servando Silva ◽  
Jacinto Figarella
Keyword(s):  
Nitrogen Fertilization ◽  
Dry Matter ◽  
Phosphorus Content ◽  
Lignin Content ◽  
Magnesium Content ◽  
Harvest Intervals ◽  
Guinea Grass ◽  
Calcium Magnesium ◽  
Nitrogen Rates ◽  
Forage Yields

The effects of nitrogen rates ranging from 0 to 1,600 pounds of N per acre yearly and of 40-, 60-, and 90-day harvest intervals on the yield and composition of Guinea grass and on soil acidity were determined for 2 consecutive years. Yields increased with nitrogen fertilization up to the 800-pound level, while protein content and protein yields increased up to the 1,600-pound level. About half of the fertilizer nitrogen was recovered in the forage when 800 pounds or less were applied per acre yearly. Efficiency of utilization, in terms of dry matter produced per pound of nitrogen, decreased with increasing rates. The phosphorus content of the forage decreased while the lignin content increased with nitrogen rates. Fertilization with nitrogen had no apparent effect on the calcium, potassium, or magnesium content of the forage. Yields and lignin content of the forage increased while the protein. phosphorus, calcium, magnesium, and potassium contents decreased with length of harvest interval. A 60-day harvest interval and 400 to 800 pounds of nitrogen per acre yearly, depending on rainfall, seemed to be the optimum combination. With the higher nitrogen rate, Guinea grass yielded 32,733 pounds of dry matter (about 73 tons of green forage) per acre yearly with 9.6 percent of protein. With this treatment Guinea grass removed about 70 pounds of phosphorus, 286 pounds of calcium, 169 pounds of magnesium, 500 pounds of nitrogen, and 330 pounds of potassium per acre yearly. About the same yields were produced during each of the two years although rainfall varied greatly. Seasonal yields varied widely. The application of 800 pounds of nitrogen as ammonium sulfate per acre annually over a 2-year period caused a drop of 2.1 pH units and a loss of 5.5 m.e. of exchangeable bases per 100 gm. in the upper 6 inches of soil.

scholarly journals Effects of Nitrogen Fertilization and Frequency of Cutting on the Yield and Composition of Napier Grass in Puerto Rico

1969 ◽  
Vol 43 (4) ◽  
pp. 215-227
Author(s):  
José Vicente-Chandler ◽  
Servando Silva ◽  
Jacinto Figarella
Keyword(s):  
Nitrogen Fertilization ◽  
Crude Protein ◽  
Dry Matter ◽  
Lignin Content ◽  
Napier Grass ◽  
Exchangeable Bases ◽  
Harvest Intervals ◽  
Calcium Magnesium ◽  
Phosphorus And Potassium ◽  
Nitrogen Rates

The effects of nitrogen rates ranging from 0 to 2,000 pounds of N per acre yearly and of 40-, 60-, and 90-day harvest intervals on the yield and composition of Napier grass and on soil acidity, were determined for three consecutive years. Yields increased with nitrogen fertilization to at least the 800-pound level during all seasons. Crude-protein contents and protein yields increased with nitrogen fertilization up to the 2,000-pound level. More than 60 percent of the fertilizer nitrogen was recovered in the forage at all rates up to 1,200 pounds per acre yearly, but efficiency of utilization in terms of dry matter produced per pound of nitrogen decreased beyond the 400- pound level. The phosphorus and potassium contents of the forage decreased, but the lignin content increased with increasing nitrogen rates. The calcium and magnesium contents were not markedly affected by nitrogen fertilization. Dry-matter and protein yields and lignin content of the forage increased, while the protein, phosphorus, calcium, magnesium, and potassium contents decreased with length of harvest interval. With a 60-day harvest interval and 800 pounds of nitrogen per acre yearly, which seemed to be the optimum combination, Napier grass yielded 44,561 pounds of dry matter, or about 130 tons of green forage, per acre yearly, containing 9.7 percent of protein. With this treatment, Napier grass removed 674 pounds of nitrogen, 554 of potassium, and 120 each of calcium, magnesium, and phosphorus per acre yearly from the soil. Over-all yields did not decrease during the 3 years of experimentation but seasonal yields varied by as much as 70 percent of the average. The treatments affected residual yields obtained more than 6 months after the experiment was terminated. The application of 800 pounds of N as ammonium sulfate per acre annually over a 3-year period caused a drop of 3 pH units and a loss of 10.4 m.e. of exchangeable bases per 100 gm. of soil in the upper 6 inches of soil.

scholarly journals Effects of Nitrogen Fertilization and Frequency of Cutting on the Yield and Composition of Para Grass in Puerto Rico

1969 ◽  
Vol 43 (4) ◽  
pp. 240-248
Author(s):  
José Vicente-Chandler ◽  
Servando Silva ◽  
Jacinto Figarella
Keyword(s):  
Protein Content ◽  
Nitrogen Fertilization ◽  
Dry Matter ◽  
Phosphorus Content ◽  
Lignin Content ◽  
Harvest Intervals ◽  
Percent Protein ◽  
Calcium Magnesium ◽  
Nitrogen Rates ◽  
Forage Yields

The effects of rates ranging from 0 to 1,600 pounds of nitrogen per acre yearly and of 40-, 60-, and 90-day harvest intervals on the yield and composition of Para grass were determined over a 1 year period. Yields increased with nitrogen fertilization up to the 800-pound level, while protein content and protein yields increased up to the 1,600-pound level. About half of the fertilizer nitrogen was recovered in the forage when 800 pounds or less were applied per acre. Efficiency of utilization in terms of dry matter produced per pound of nitrogen, decreased rapidly with increasing rates. The phosphorus content of the forage decreased while the lignin content increased with nitrogen rates. Nitrogen fertilization had no pronounced effect on the calcium, potassium, or magnesium contents of the forage. Yields and lignin content of the forage increased while protein, phosphorus, calcium, magnesium, and potassium contents decreased with length of harvest interval. There are marked seasonal variations in yield due primarily to rainfall. With a 60-day harvest interval and 800 pounds of nitrogen per acre yearly, Para grass yielded 30,841 pounds of dry forage, or about 70 tons of green forage, with a 9.5-percent protein content. With this treatment Para grass removed 52.4 pounds of P, 120 of Ca, 524 of K, 77 of Mg, and 469 pounds of N per acre yearly. It is not advisable to use rates of more than 400 pounds of nitrogen per acre per year during dry weather.

scholarly journals Description and Cytology of a Form of Signal Grass (Brachiaria brizantha Stapf.) and its Agronomic Behavior Compared to Guinea Grass (Panicum maximum Jack.)

1969 ◽  
Vol 44 (4) ◽  
pp. 208-220
Author(s):  
A. Sotomayor-Ríos ◽  
J. Vélez-Fortuño ◽  
R. Woodbury ◽  
K. F. Schertz ◽  
A. Sierra-Bracero
Keyword(s):  
Puerto Rico ◽  
Mineral Content ◽  
Lignin Content ◽  
Panicum Maximum ◽  
Somatic Chromosome Number ◽  
Brachiaria Brizantha ◽  
Important Place ◽  
Forage Crop ◽  
Guinea Grass ◽  
Signal Grass

The somatic chromosome number of a form of Signal grass (Brachiaria brizantha Stapf.), Puerto Rico P.I. No. 1525, introduced from Ceylon, was found to be 36. Only 15 percent of the florets studied developed karyopses. The meiotic behavior of chromosomes at microsporogenesis was irregular. Frequent lagging univalents at anaphase 1 and micronuclei in the spore quartets may account for the low seed-set of this form. More improvement of this character is expected in Signal grass through further research in genetics and by the introduction of more forms and varieties. A field description of Signal grass is given. Signal grass was compared to Guinea grass (Panicum maximum Jack.) as to agronomic behavior. It showed desirable characteristics, besides yielding the same as Guinea grass, one of our best forage grasses, when both grasses were tested at the Gurabo Substation for a period of 530 days. The mineral content of the grasses under this experiment was comparable, but calcium and magnesium were definitely higher in Guinea grass. The lignin content of Signal grass was lower than that of Guinea grass; this difference, although small in favor of Signal grass, may have more importance in terms of animal digestibility than the chemical analyses indicate. The results obtained in relation to yielding ability and drought-resistance of this form of Signal grass are very encouraging. As the palatability of this grass has been found to be comparable to that of Napier grass, which is the standard grass used for palatability tests at this Station, it may be expected to occupy in due time a very important place as a forage crop throughout the Island of Puerto Rico, especially in the drought areas.

scholarly journals Grain yield and kernel crude protein content increases of maize hybrids with late nitrogen side-dressing

2005 ◽  
Vol 62 (5) ◽  
pp. 487-492 ◽  
Author(s):  
Paulo Regis Ferreira da Silva ◽  
Mércio Luiz Strieder ◽  
Rúbia Patrícia da Silva Coser ◽  
Lisandro Rambo ◽  
Luís Sangoi ◽  
...  
Keyword(s):  
Grain Yield ◽  
Protein Content ◽  
Nitrogen Fertilization ◽  
Crude Protein ◽  
Yield Response ◽  
Crude Protein Content ◽  
Vegetative Development ◽  
Maize Hybrids ◽  
Nitrogen Rates ◽  
The Impact

Physiological changes incorporated into current maize hybrids suggest the occurrence of modifications in the nitrogen uptake dynamics, improving plant ability to uptake N during grain filling. This may justify late N side-dressing whenever environmental constraints prevent adequate nitrogen supply during crops vegetative development. This study evaluates effects of nitrogen fertilization at booting and silking on grain yield and kernel crude protein contents of commercial maize hybrids. Two experiments were set up in Eldorado do Sul, RS, during the 2001/2002 and 2002/2003 growing seasons. In 2001/2002, treatments were composed of two hybrids (Agroceres 303 and Pioneer 32R21), three nitrogen rates applied during maize vegetative development (30, 80 and 130 kg ha-1) and three nitrogen rates applied at silking (0, 50 and 100 kg ha-1). In 2002/2003, four hybrids (Agroceres 303, Pioneer 32R21, Dekalb 215 and Syngenta Penta) and four nitrogen rates side-dressed at booting (0, 50, 100 and 150 kg.ha-1) were assessed. There were significant increments in grain yield and kernel crude protein content with nitrogen fertilization at booting and silking. Grain yield response to late N side-dressing differed among cultivars. The impact of nitrogen fertilization at silking was higher at the smallest rate of N during the plant vegetative development. Enhancements in grain yield with late N side-dressing resulted from increases in grain weight. Modern hybrids can uptake nitrogen during silking, contradicting the hypothesis that late N side-dressing is not efficient to improve maize grain yield.

scholarly journals Effect of Nitrogen Rates, Harvest Interval and Cutting Heights on Yield and Composition of Star Grass in Puerto Rico

1969 ◽  
Vol 56 (3) ◽  
pp. 267-279
Author(s):  
Rubén Caro-Costas ◽  
Fernando Abruña ◽  
Jacinto Figarella
Keyword(s):  
Puerto Rico ◽  
Protein Content ◽  
Crude Protein ◽  
Dry Matter ◽  
Lignin Content ◽  
Harvest Intervals ◽  
The Difference ◽  
Percent Nitrogen ◽  
Cutting Height ◽  
Nitrogen Rates

The effect of nitrogen rates, length of harvest intervals, and cutting heights on the yield and composition of a Puerto Rico cultivar of Star grass were determined during 2 consecutive years. Dry matter yields increased with nitrogen rates at the two cutting heights tested. However, the response at the various harvest intervals tested (30, 45, 60 and 90 days) was dependent on cutting height. Low cut Star grass responded sharply up to 400 to 600 pounds of nitrogen depending on harvest interval. High cut Star grass responded sharply to 400 to 600 pounds of nitrogen depending on harvest interval. The crude protein yield and content increased up to the highest nitrogen rate tested at all harvest intervals and cutting heights. The percent nitrogen recovered in the forage was of the same magnitude as that obtained with other grasses. However, the nitrogen rates did not have a pronounced effect on the percent nitrogen recovered in the forage. The proportion of leaves to stems was not affected by nitrogen rates. Leaves were higher in protein content than the stems at all nitrogen rates and harvest intervals. Dry matter yields increased but protein content decreased as length of harvest interval increased from 30 to 90 days. Length of harvest interval did not affect the percent nitrogen recovered in the forage, but had a marked effect on chemical composition of the forage. The content of N, P and K decreased at both cutting heights and at all nitrogen rates as the length of the harvest interval increased from 30 to 90 days. The apparent digestibility of the forage decreased and lignin content increased as length of harvest interval increased. Star grass produced higher yields when cut low than high. The difference was more evident as the length of the harvest interval increased from 30 to 90 days.

scholarly journals Performance of Six Cenchrus and Four Panicum Forage Grasses Under Cutting Management in the Lajas Valley, Puerto Rico

1969 ◽  
Vol 66 (4) ◽  
pp. 268-277
Author(s):  
J. Vélez-Santiago ◽  
A. Sotomayor-Ríos ◽  
S. Torres-Rivera ◽  
A. V. Méndez-Cruz
Keyword(s):  
Puerto Rico ◽  
The Other ◽  
Forage Grasses ◽  
Guinea Grass ◽  
Cutting Experiment ◽  
Cutting Management ◽  
Forage Yields ◽  
Short Days ◽  
Semi Arid

Common guinea grass and new accessions of Panicum and Cenchrus grasses were evaluated in a cutting experiment in the semi-arid Lajas Valley over three periods: 126 days of cool weather and short days; 378 days; and nearly 2 years (672 days). The grasses were fertilized with 3,360 kg.ha-1 of a 15-15-10 fertilizer, divided in eight equal applications. The grasses were irrigated. The grasses were harvested every 42 days. In the 126-day period of short cool days, buffel 13084 and guinea 12917 were the highest dry forage yielders, with 11,371 and 11,061 kg.ha-1, respectively. In the 378-day period, guinea #13093, #12917 and #13092 produced statistically similar dry forage yields, which were higher than those of the other grasses. Among the Panicum grasses, guinea 13093 was the highest dry forage yielder (45,574 kg. X-1); among the Cenchrus grasses, buffel 13084 was the highest yielder (35,247 kg. X-1). In the 672-day period, guinea #13093, #13092, and #12917 outyielded var. common and all buffel grasses.

scholarly journals Effect of Liming and Fertilization on Productivity and Species Balance of a Tropical Kudzu-Molassesgrass Pasture Under Grazing Management

1969 ◽  
Vol 47 (4) ◽  
pp. 236-241
Author(s):  
Rubén Caro-Costas ◽  
José Vicente-Chandler
Keyword(s):  
Puerto Rico ◽  
Chemical Composition ◽  
Nitrogen Fertilization ◽  
Manganese Content ◽  
Grazing Management ◽  
Mountain Region ◽  
High Manganese ◽  
Phosphorus And Potassium ◽  
Forage Yields ◽  
High Manganese Content

The effects of lime, phosphorus, potassium, and nitrogen applications on the productivity, species balance, and chemical composition of a tropical kudzu-molassesgrass mixture growing under grazing management on a latosol in the Humid Mountain Region of Puerto Rico were determined. Yields of tropical kudzu and molassesgrass, and the proportion of kudzu in the mixture were increased by combined applications of lime, phosphorus, and potassium. Yields and species balance were not affected by applications of phosphorus or potassium individually when no nitrogen was applied. However, when nitrogen was applied, the pastures responded in yield to applications of potassium but species balance was not affected. Liming increased both yields of kudzu and the proportion of this legume in the mixture about fivefold. Liming also increased the protein and calcium contents of tropical kudzu and sharply reduced the abnormally high manganese content of unlimed kudzu. The application of 200 pounds of nitrogen per acre yearly increased forage yields, but resulted in the virtual disappearance of tropical kudzu from the mixture. Heavier applications of nitrogen did not further increase yields, but resulted in a marked invasion of the pastures by Para grass. It is apparent that yields of tropical kudzu-molassesgrass pastures cannot be increased much by nitrogen fertilization without erradicating the kudzu. However, if kudzu becomes dominant, as is often the case, it may be possible to restore a desirable species balance by judicious applications of nitrogen.

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